Answer: Black spot typically attacks rose bushes and a neem oil based product called Rose Defense can be used to keep the disease under control. As for your palm tree, the white powder is a fungus called powdery mildew, and that's not good news for your palm! This fungus will be hard to eradicate without stressing the palm; however all you can do is try, so spray the palm with a broad spectrum fungicide, and let the soil dry between waterings. Cut back the dead fronds, and let mother nature take its course.
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